Apparatus for coupling a drive motor to a leader block loading/unloading mechanism

ABSTRACT

A take-up assembly for operating a mechanism for loading and unloading the leader block of a tape cartridge, and for receiving the web of tape which it contains for subsequent transport, stores energy for transfer to the leader block loading/unloading mechanism when it is to operate to load or unload the leader block, so that even a conventional take-up motor is made capable of supplying the increased energy needed for leader block loading/unloading. 
     A preferred take-up assembly includes a hub which is directly coupled to the take-up motor and which serves to receive the web of tape for direct transport, and a coupling which is nested within the hub and which receives the leader block loading/unloading mechanism. A pin depends from the coupling and into a circumferentially arranged slot formed inthe hub, to connect the hub and coupling as the pin engages the ends of the slot.

BACKGROUND OF THE INVENTION

The present invention relates generally to the storage of data onmagnetic recording tape, and in particular, to the storage of data onmagnetic tape in cartridge form.

In the course of developing various systems for the storage of data onmagnetic recording tape, particularly off-line storage of data in theform of back-up storage, a variety of different formats have beendeveloped. Many of these formats call for the tape to be contained in anappropriate cartridge, both to facilitate handling of the tape while inuse, and to protect the tape while in storage.

Recently, IBM Corporation has announced a tape cartridge which isprimarily intended for use in its Model 3480 data storage system, forthe storage of relatively large quantities of data (on the order of 200megabytes). Details regarding the construction of this type of tapecartridge (hereinafter referred to as a 3480 tape cartridge) may be hadwith reference to U.S. Pat. No. 4,452,406. By way of generaldescription, the 3480 tape cartridge is comprised of a single reelcontaining a quantity of magnetic tape and contained in a rectangularenclosure having dimensions on the order of 4 inches in width, 5 inchesin length, and 1 inch in height. The cartridge enclosure includes anaperture in one of its major faces, to receive means for rotating thereel of tape contained within the cartridge, and an aperture in one ofits corners, for gaining access to the free end of the web of tape. Aso-called "leader block" is connected to the free end of the tape, andis frictionally received within the open corner of the cartridge so thatit is capable of being withdrawn from and replaced within the cartridgeby appropriate means.

In connection with the 3480 tape cartridge, IBM Corporation has alsodeveloped equipment for receiving the tape cartridge and for properlyplacing the web of tape which it contains in operative association witha magnetic read/write head. Further details regarding such equipment maybe had with reference to U.S. Pat. Nos. 4,432,508; 4,399,959; 4,399,936;and 4,335,858, which illustrate various different devices which havebeen developed by the IBM Corporation to accommodate its 3480 tapecartridge.

Unlike many of the other types of tape cartridges which have beendeveloped for use in the off-line storage of data, the IBM 3480 tapecartridge houses only a single reel of magnetic recording tape. Theleader block which is connected to the free end of the web of tape isused to introduce the web of tape to the transport apparatus (and theread/write head). To this end, the transport apparatus must be providedwith appropriate means for withdrawing the leader block from its nestingwithin the 3480 tape cartridge, and for threading the leader block (andthe web of tape) through the apparatus and past the read/write head. Ofcourse, means must also be provided for unthreading the web of tape (andthe leader block) from the apparatus, and for replacing the leader blockwithin its nesting in the 3480 tape cartridge. In connection with suchoperations, there are two major considerations which bear noting.

First, special means must be provided to engage the leader blockassembly, and to guide the leader block (and the tape which follows)through the transport apparatus which is to operate upon the web oftape. This requires care in withdrawing the leader block from the tapecartridge, and in guiding the web of tape from the supply reel of thetape cartridge, past the read/write head, and into engagement with thetake-up reel which is traditionally provided to cooperate with thesupply reel in transporting the web of tape through the apparatus andpast the read/write head. This necessitates the development of anappropriate path for threading the leader block through the apparatus,as well as means which have sufficient driving forces to withdraw theleader block from its normally seated position within the tapecartridge, and to replace the leader block within this normally seatedposition after the tape cartridge has been used. To meet these needs, aswell as other design requirements regarding data density and performancecharacteristics, those devices described in the above-identified U.S.Patents each make use of a loading mechanism which is essentiallyseparate from the remainder of the apparatus which is used to operateupon the magnetic recording tape. In each case, a track or groove isprovided for guiding the leader block through the desired tape path andto the take-up reel, under the influence of a dedicated driving meanswhich is separate from the various components comprising the tapetransport. Although several different mechanisms are described, in eachcase a separate motor and track/groove drive is provided to achieveproper interfacing of the web of tape with the apparatus.

Second, as with any magnetic tape recording apparatus, care must betaken to develop a proper tape path between the supply and take-upreels, and across the read/write head, to assure proper registration ofthe tape with the read/write head. The primary consideration in thisregard is one of length, since the tape path must generally be longenough to accommodate distortion of the tape as the web of tape is drawnthrough the apparatus, as a result of mechanical irregularities in theapparatus. To this end, those devices described in the above-identifiedpatents each provide a tape path of significant length, to account forsuch potential irregularities. A secondary consideration is that caremust be taken to avoid undesirable contact between the oxide coatingprovided on the web of magnetic recording tape, and components of theapparatus other than the read/write head, such as bearings and idlerrollers. When the IBM 3480 tape cartridge is used as intended in thevarious devices described in the above-identified patents, the oxidecoating (formed on the inner most face of the tape on the supply reel)normally faces toward the interior of the transport apparatus due to itsorientation. As a result of this placement, as the tape is threadedthrough the transport apparatus the potential exists for the oxidecoating to be drawn across various of the guiding structures associatedwith the apparatus. Since contact with such structures can compromisethe useful life of the tape cartridge, and give rise to a potential formemory loss in the event that portions of the oxide coating becomedamaged, special care is taken to avoid contact between the oxidecoating and those guiding structures which the oxide coating couldpotentially contact. For example, air-bearings are provided on eitherside of the read/write head to avoid contact between the bearings andthe web of tape which passes across them.

As a result of these and other design considerations, those deviceswhich have been developed to operate upon IBM 3480 tape cartridges havegenerally been large, cumbersome and expensive. While this can bejustified in connection with relatively large, mainframe applications,such design constraints have significantly limited, if not totallyprecluded use of the 3480 tape cartridge in connection with relativelylow cost, minicomputer or microcomputer applications.

Yet another consideration which has inhibited use of the 3480 tapecartridge in mini/micro-computer applications is one of space. It isgenerally impractical, and therefore undesirable, to necessitate thepurchase of an apparatus for off-line, back-up storage or the like whichis significantly larger than the primary equipment which the apparatusis to support. In fact, due to the prevalent use of 51/4 inch magneticrecording (floppy) discs in connection with such applications, a defacto standard has come about for any form of storage equipment (floppydisc, hard disc, cartridge, etc.) which is to replace or relate to suchconventional storage means. The recognized "form factor" or "footprint"of a standard 51/4 inch magnetic recording disc calls for a container orhousing having dimensions on the order of 53/4 inches in width, 8 inchesin depth and 31/4 inches in height. Those devices described in theabove-identified patents are not adaptable to such applications.

Accordingly, limitations of cost and size significantly limited theability to use the IBM 3480 tape cartridge in mini/micro-computerapplications. To extend the usefulness of the 3480 tape cartridge tomini/micro-computer applications, co-filed and commonly owned U.S.patent application Ser. Nos. 842,446 and 842,450, in the name of JaySmith and entitled "Apparatus for Loading and Unloading the Leader Blockof a Tape Cartridge", the subject matter of which are incorporated byreference as if fully set forth herein, describe a simplified means forloading and unloading the leader block of a 3480 tape cartridge, makinguse of a loading/unloading mechanism which is directly associated withthe take-up reel of the apparatus rather than a separate mechanism. Tothis end, the take-up reel of the apparatus is provided with a linkagewhich extends from the periphery of the take-up reel, and which has apin for engaging the leader block of the tape cartridge. The pin of thelinkage is caused to proceed along a specified path, following a cammingsurface under the influence of an over-center spring, to achieveeffective tranfer of the leader block from the tape cartridge, throughits specified tape path, to the take-up reel, and vice versa.Consequently, leader block loading and unloading is accomplished withoutrequiring the use of an additional drive mechanism for this purpose,significantly reducing the number of components of the apparatus, andenabling the apparatus to be reduced to a size which can be fit within astandard 51/4 inch footprint or form factor.

However, the energy required to withdraw the leader block from the tapecartridge, as well as to later replace the leader block within the tapecartridge, is significantly greater then the energy required totransport tape within the apparatus. Consequently, it has been foundthat conventional take-up motors are generally insufficient to alsooperate the leader block loading/unloading mechanism. Increasing thecapabilities of the take-up motor would overcome this problem, but onlyat the expense of increased costs, size and/or input power requirements.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide anapparatus for receiving and operating upon an IBM 3480 tape cartridge,which is sufficiently compact to fit within a standard 51/4 inchfootprint or form factor without compromising performance of the tapecartridge or the conventional components of the apparatus.

It is also an object of the present invention to provide a take-upassembly for both receiving and operating upon the web of tape containedin the tape cartridge, using a single motor drive.

It is also an object of the present invention to provide a take-upassembly for both receiving and operating upon the web of tape, using aconventional take-up motor.

It is also an object of the present invention to provide such means inan apparatus which is simple and reliable in operation, and which iscost effective even in connection with mini/micro-computer applications.

These and other objects are achieved according to the present inventionby providing a take-up assembly which is capable of both operating amechanism for loading and unloading the leader block of a 3480 tapecartridge, and receiving the web of tape for subsequent transport, byproviding sufficient energy for transfer to the leader blockloading/unloading mechanism when it is to operate to load or unload theleader block. As a consequence of this, even a conventional take-upmotor is made capable of supplying the increased energy needed forleader block loading/unloading, eliminating the need to increase eitherthe capacity of the motor, or the supplied currents.

A preferred take-up assembly according to the present invention includesa hub which is directly coupled to the take-up motor and which serves toreceive the web of tape for direct transport, and a coupling which isnested within the hub and which receives the leader blockloading/unloading mechanism. A pin depends from the coupling and into acircumferentially arranged slot formed in the hub, to connect the huband coupling as the pin engages the ends of the slot. The length of theslot defines an angle which, in combination with the moment arm definedbetween the axis of the take-up assembly and the leader blockloading/unloading mechanism, develops a torque output which is sufficentto withdraw or replace the leader block, as desired, making use of anotherwise conventional take-up motor (one which is ordinarily onlyrequired to transport tape).

For further detail regarding the improvements of the present invention,reference is made to the following detailed description, taken inconjunction with the following illustrations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an apparatus for operating upon a tapecartridge in accordance with the present invention, showing the tapecartridge as it is initially received within the apparatus.

FIG. 2 is a partially sectioned, side elevation view of the apparatusshown in FIG. 1.

FIG. 3 is an exploded, isometric view of the take-up reel of theapparatus shown in FIG. 1.

FIG. 4 is a top plan view similar to FIG. 1, showing operation of theapparatus as the leader block is returned to the tape cartridge.

In the several views provided, like reference numerals denote similarstructure.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Although specific forms of the invention have been selected forillustration in the drawings, and the following description is drawn inspecific terms for the purpose of describing these forms of theinvention, this description is not intended to limit the scope of theinvention which is defined in the appended claims.

FIGS. 1 and 2 show a transport apparatus 1 for receiving and operatingupon an IBM 3480 tape cartridge 2 in accordance with the presentinvention. To be noted is that the apparatus 1 is sufficiently compactto be received within the confines of a standard 51/4 inch form factoror footprint.

The tape cartridge 2 generally comprises a quantity of tape 5 wound upona supply reel 6 and contained within a housing 7. Suitable means(preferably a geared, magnetic coupling) are provided for placing thesupply reel 6 in operative association with a supply motor 3 positionedbeneath the surface 8 of the transport apparatus 1. A corner 9 of thehousing 7 is open, and receives a leader block 10, which is used tosecurely engage the free end 11 of the web of tape 5 in the mannershown. As produced by the manufacturer, the inwardly facing surface 12of the web of tape 5 is provided with the requisite oxide coating.

The web of tape 5 is preferably received within the transport apparatus1 so that the leader block 10 is remote from the operative features ofthe transport apparatus 1, to improve the available tape path, and sothat the surface 12 of the web of tape 5 faces generally outwardly asthe web of tape 5 is withdrawn from the tape cartridge 2 and introducedinto the transport apparatus 1, to avoid the potential for contact withsuch operative features. To this end, the tape cartridge 2 is receivedwithin the transport apparatus 1 along a side edge 13, rather than beingreceived along its rear edge 14, in the usual manner. This essentiallyrotates the tape cartridge 2 through an angle of 90°, so that the leaderblock 10 is positioned along the left side of the transport apparatus 1,as viewed from its front, rather than its usual placement along theright side of the transport apparatus 1. Means for receiving the tapecartridge 2 in this orientation, and for readying the tape cartridge 2and the leader block 10 for further use, are described with reference toa co-filed and commonly owned U.S. patent application Ser. No. 842,449,in the name of Arnold Schonfeld and Robert Lane and entitled "ApparatusFor Loading and Unloading a Tape Cartridge", the subject matter of whichis incorporated by reference as if fully set forth herein.

Once received within the transport apparatus 1, the tape cartridge 2 isthen readied for further operation as follows. First, the supply reel 6is operatively connected to the supply motor 3 which is positionedbeneath the surface 8 of the transport apparatus 1, so as to achievedesired rotation of the supply reel 6 in accordance with the selectedmode of operation of the transport apparatus 1. Second, a configured pin16 is brought into engagement with the slot 17 (and counterbore 17a)which is conventionally provided in the leader block 10 of the tapecartridge 2, so as to operatively connect the leader block 10 with theleader block loading/unloading mechanism 20, and ready the leader block10 for loading into the transport apparatus 1 as will be described morefully below.

The leader block loading/unloading mechanism 20 is generally comprisedof three major components including a configured take-up reel 21, acontoured camming surface 22, and an articulating engagement mechanism23.

The take-up reel 21 is operatively connected to a take-up motor 19 by aconcentric hub 24 and coupling 25, as is best illustrated with referenceto FIG. 3. The hub 24 is attached to the take-up motor 19, and includesa concentric wall 24a which serves to receive the web of tape 5. Thecoupling 25 is nested within the hub 24, and is operatively connected tothe hub 24 by a peg 27 which depends from the coupling 25 and into aconcentrically arranged slot 26 formed in the hub 24.

The coupling 25 is additionally provided with a cavity 28 which iscorrespondingly configured to the leader block 10 of the tape cartridge2, and the wall of the hub 24 is provided with a corresponding slot 32which permits communication with the cavity 28 of the coupling 25 uponproper alignment of the hub 24 and coupling 25 as will become apparentfrom the description which follows. The cavity 28 is preferablyconfigured to securely receive the leader block 10 so that the rear face29 of the leader block 10 fills the slot 32 and co-terminates with theperiphery of the hub wall 24a, essentially completing the periphery ofthe hub 24 so as to properly receive the web of tape 5. The uppersurface 30 of the coupling 25 is provided with a flange 31 which, as asecondary function serves to retain the web of tape 5 to the take-upreel 21, and as a primary function serves to receive the articulatingengagement mechanism 23, at the pivot 35.

The articulating engagement mechanism 23 is generally comprised of twoarms 36, 37. The primary arm 36 terminates at the pin 16 which is usedto engage the slot 17 of the leader block 10. The opposite end 38 of theprimary arm 36 is connected to the secondary arm 37, at a pivot 39.Respective articulation of the arms 36, 37 is regulated by a spring 40which is connected between an attachment point 41 fixed on the primaryarm 36 and an attachment point 42 fixed on a flange 45 attached to andprojecting from the secondary arm 37, toward the take-up reel 21. Thespring 40 is pivotally connected between the arms 36, 37 so that thespring is caused to proceed through an "over-center" position wherein incertain orientations, compression of the spring 40 will cause the arm 36to rotate in a clockwise direction with respect to the arm 37, while inother orientations, compression of the spring 40 will cause the arm 36to rotate in a counter-clockwise direction with respect to the arm 37.Such rotation is responsive to the position of the pivot 39 with respectto the line of forces developed between the attachment points 41, 42.

The contoured camming surface 22 is positioned above the flange 31 ofthe take-up reel 21 so that the take-up reel 21 and the articulatingengagement mechanism 23 are capable of movement beneath the contouredcamming surface 22, but so that the upper end 43 of the pin 16 iscapable of following the face 44 of the contoured camming surface 22 toachieve loading and unloading of the leader block 10.

The loading/unloading mechanism 20 generally serves to transfer theleader block 10 of the tape cartridge 2 from its seated position withinthe corner 9 of the housing 7, past a read/write head 50, and to thecavity 28 formed in the take-up reel 21, so that the web of tape 5 isready for transport between the supply reel 6 and the take-up reel 21under the influence of the motor 3, 19. However, as previouslydescribed, because of the manner in which the leader block 10 is seatedwithin the tape cartridge 2, the amount of energy (torque acting throughan arc of rotation) required to withdraw the leader block 10 from thehousing 7 is significantly greater than the amount of energy normallyrequired for tape transport. In accordance with the present invention,sufficient energy is provided for removal of the leader block 10, makinguse of a conventional take-up motor 19, by causing the hub 24, andtherefore the slot 26, to rotate with an appropriate torque through adefined angle (θ) until such time as the peg 27 engages the end 49 ofthe slot 26, directly coupling the motor 19 to the coupling 25. Thus,the amount of energy produced in this fashion relates to the torqueapplied through the angle (θ) defined by the slot 26.

Accordingly, to unload the leader block 10 from the tape cartridge 2,the hub 24 is moved in a clockwise direction from a first position inwhich the end 47 of the slot 26 engages the pin 27, to a second positionin which the end 49 of the slot 26 engages the pin 27, under theinfluence of the take-up motor 19 (which is preferably microprocessorcontrolled to accomplish this function). The energy resulting from suchmovement, which is stored in angular velocity of the mass of the take-upmotor 19 and the hub 24 during motion of the pin 27 in the slot 26, andtransferred via the impact of the pin 27 with the end 49 of the slot 26to the articulating engagement mechanism 23, has been found to besufficient to cause a retraction of the articulating engagementmechanism 23 which is sufficient to snap the leader block 10 from itsnesting within the housing 7. Engagement between the primary arm 36 anda pivot block 48, at the interface 51, has been found to be ofparticular importance in directing the forces applied to the leaderblock 10 so that the leader block 10 is reliably withdrawn from thehousing 7 in the course of the foregoing operations.

Further retraction of the articulating engagement mechanism 23responsive to continued clockwise rotation of the take-up reel 21 causesthe pin 16 (with the leader block 10 attached) to progress generally tothe left, bringing the upper end 43 of the pin 16 into engagement withthe face 44 of the contoured camming surface 22. Upon continuedclockwise rotation of the take-up reel 21, the spring 40 serves to urgethe pin 16 into the face 44 of the contoured camming surface 22, causingthe pin 16 to progress along the defined contour. This, in turn, drawsthe leader block 10, and the web of tape 5, around a first idler roller46, past a pair of bearings 52, and around yet another idler roller 53,for eventual delivery to the take-up reel 21.

Further clockwise rotation of the take-up reel 21 causes the leaderblock 10 to enter the cavity 28. To enable the leader block 10 to enterthe cavity 28, two considerations arise. First, the leader block 10 mustarrive in general alignment with the cavity 28 as the take-up reel 21 isrotated. Such dynamic placement of the leader block 10 is accommodatedby the configuration of the articulating engagement mechanism 23.Second, the slot 32 in the hub 24 must be aligned with the cavity 28 inthe coupling 25 for the leader block to enter the cavity 28. This isaccomplished by properly placing the slot 32 in relation to the slot 26of the hub 24, so that the slot 32 and the cavity 28 are brought inalignment when the peg 27 contacts the end 49 of the slot 26 aspreviously described.

As the leader block 10 enters the cavity 28, the line of forces of theover-center spring 40 as defined by the attachment points 41, 42 crossesthe pivot 39. As a consequence of this, the spring 40 now serves to urgethe leader block 10 inwardly toward the center of the take-up reel 21,assuring that the leader block 10 becomes fully and firmly seated withinthe cavity 28. As a result, the periphery of the hub 24 becomescompleted by the surface 29 of the leader block 10, permitting the webof tape 5 to be wound around the take-up reel 21 for subsequenttransport between the supply reel 6 and the take-up reel 21 in otherwiseconventional fashion. To be noted is that this results in a positiveengagement of the web of tape 5 by a hub 24 which is rigidly coupled tothe take-up motor 19, so as to assure that the web of tape 5 is properlytransported in accordance with generally recognized principles.

Of course, the web of tape 5 must be transported between the supply reel6 and the take-up reel 21 in a manner which assures that the surface 12of the web of tape 5 is in proper contact with the read/write head 50.In delivering the leader block 10 to the take-up reel 21 as previouslydescribed, it is generally necessary to provide a significant spacebetween the read/write head 50 and the plane of the bearings 52, toenable passage of the leader block 10. Accordingly, to develop propercontact with the read/write head 50 it becomes necessary to reorient thebearings 52 so as to develop a proper tape wrap about the read/writehead 50, in accordance with recognized practices. Further detailsregarding such structure may be had with reference to a co-filed andcommonly owned U.S. patent application Ser. No. 842,448, in the name ofDaniel Sachuk and entitled "Retractable Tape Guide", the subject matterof which is incorporated by reference as if fully set forth herein.

Having properly threaded the web of tape 5 through the transportapparatus 1, and having placed the oxide surface 12 of the web of tape 5in appropriate contact with the read/write head 50, desired transfers ofdata may then take place in otherwise conventional manner. This proceedsuntil such time as the transfer of data has been completed and the tapecartridge 2 is to be unloaded from the transport apparatus 1.

In essence, this is accomplished by reversing the above described steps.The supply motor 3 is rotated in a clockwise direction until such timeas the web of tape 5 is fully unwound from the take-up reel 21.Continued clockwise rotation of the supply motor 3 serves to pull theleader block 10 from the cavity 28, and to draw the leader block 10along the face 44 of the camming surface 22, until such time as the webof tape 5 and the end 29 of the leader block 10 are returned to thehousing 7 of the tape cartridge 2, and the end of the leader block 10which is engaged by the pin 16 is in a position just outside of itsnesting in the corner 9 of the tape cartridge 2, with reference to FIG.4.

Since the energy required for replacement of the leader block 10 willagain exceed the normal capabilities of the take-up motor 19, furtheraction upon the reels 6, 21 is needed to force the leader block 10 intoits nesting in the corner 9 of the tape cartridge 2. The energy requiredto fully snap the leader block 10 into the housing 7 is again primarilysupplied by the hub 24 which connects the take-up reel 21 to the drivemotor 19. As previously described in connection with unloading of theleader block 10, the kinetic energy needed to return the leader block 10to its nesting is again capable of being developed by rotating the hub24 through the specified angle (θ) so as to cause the slot 26 of the hub24 to slip with respect to the peg 27 of the coupling 25, this time fromthe end 49 to the end 47. A reaction wall 67 is provided to limitmovement of the articulating engagement mechanism 23 (in the directionof arrow 68), to transmit the forces developed under the influence ofthe take-up motor 19 in an appropriate direction to snap the leaderblock 10 back into the housing 7. After such steps have been taken toseat the leader block 10 in the housing 7, an appropriate torque may beapplied to the motor 19, if desired, to test the seating of the leaderblock 10 and make sure that it has been fully snapped back into thehousing 7.

It will therefore be seen that the foregoing apparatus serves well tosatisfy each of the objectives previously set forth. The means used toload and unload the leader block 10 are directly associated with thetake-up reel 21, and are capable of accomplishing leader block loadingand unloading, as well as tape transport, using an otherwiseconventional take-up motor 19.

It is also to be understood that the foregoing is capable of variationwithout departing from the spirit and scope of the present invention.For example, the configuration of the hub 24 and coupling 25 may bevaried, as may the means which are used to interconnect such structures.To be noted is that in the foregoing description, a slot 26 is formed inthe hub 24 and a pin 27 is provided in the coupling 25. It is equallypossible for these structures to be reversed, if desired. The angle (θ)developed in accordance with the present invention is also capable ofvariation to provide the torques required for proper operation of theapparatus as previously described. Moreover, the interactive coupling ofthe present invention will find applicability to other tape transports,apart from the transport previously described, or even to other deviceswhich exhibit similar requirements.

It will therefore be understood that various changes in the details,materials and arrangement of parts which have been herein described andillustrated in order to explain the nature of this invention may be madeby those skilled in the art within the principle and scope of theinvention as expressed in the following claims.

What is claimed is:
 1. In a transport apparatus for receiving andoperating upon a tape cartridge including a web of tape disposed on asupply reel and having a free end engaged by a leader block nestedwithin said tape cartridge, and including a take-up reel fortransporting said web of tape between said supply reel and said take-upreel responsive to a motor, wherein the energy required to withdraw theleader block from said nesting exceeds the energy required to transportsaid web of tape and the capacity of said motor:means associated withsaid take-up reel for engaging the leader block of said tape cartridgeand for delivering said leader block from the nesting of said tapecartridge to said take-up reel; and means associated with said take-upreel for transferring stored energy to said leader block engaging meansto enable said leader block to be withdrawn from said nesting,comprising a hub connected to said motor and including a cylindricalwall for receiving said web of tape, a coupling nested within said huband including a cavity for receiving said leader block, a flange forreceiving said leader block engaging means, and means for causing saidhub and coupling to rotate with respect to one another for a defined arcupon rotation of said hub by said motor.
 2. The apparatus of claim 1wherein said means for causing said hub and coupling to rotate withrespect to one another is a slot formed in said hub, and a peg dependingfrom said coupling and slidingly engaging said slot.
 3. The apparatus ofclaim 2 wherein said arc is defined by the length of said slot.
 4. Theapparatus of claim 3 wherein said defined arc is selected according tothe energy required to withdraw the leader block from said nesting. 5.The apparatus of claim 1 wherein a reaction point is provided fordirecting forces applied to said leader block when said leader block isto be withdrawn from said tape cartridge.
 6. The apparatus of claim 1wherein the energy required to replace the leader block within saidnesting exceeds the energy required to transport said web of tape andthe capacity of said motor and including means associated with saidtake-up reel for transferring stored energy to said leader blockengaging means to also enable said leader block to be replaced in saidnesting.
 7. The apparatus of claim 6 wherein a reaction point isprovided for directing the forces applied to said leader block when saidleader block is to be replaced in said tape cartridge.
 8. In a transportapparatus for receiving and operating upon a tape cartridge including aweb of tape disposed on a supply reel and having a free end engaged by aleader block nested within said tape cartridge, and having a hub forreceiving said leader block and said web of tape, and for transportingsaid web of tape responsive to a motor:a coupling for operativelyconnecting said hub and said motor to a means for engaging said leaderblock and for withdrawing said leader block from said tape cartridge fordelivery to said hub, wherein the energy required to withdraw the leaderblock from said nesting exceeds the energy required to transport saidweb of tape and the capacity of said motor, said coupling including apeg depending from said coupling and slidingly engaging a slot in saidhub so that said peg and said slot are capable of sliding with respectto one another to transferring stored energy to said leader blockengaging means to enable said leader block to be withdrawn from saidnesting.
 9. The apparatus of claim 8 wherein said slot is elongated foran arc defined according to the energy required to withdraw the leaderblock from said nesting.
 10. The apparatus of claim 8 wherein the energyrequired to replace the leader block within said nesting exceeds theenergy required to transport said web of tape and the capacity of saidmotor, and wherein said peg and said slot are capable of sliding withrespect to one another to transferring stored energy to said leaderblock engaging means to enable said leader block to be replaced withinsaid nesting.